An NHS watchdog is to develop guidelines for surgeons to help minimisethe risk of contracting CJD infections through operations.

It will advise on surgical procedures and instruments used in operationsinvolving tissues carrying a high or medium risk CJD or Variant CJD.

The finished document is not expected until May 2006.

The National Institute for Clinical Excellence will not examine therisks posed by blood transfusions, however.

Last month, 4,000 patients in the UK were sent letters warning them theymay have been exposed to vCJD through contaminated blood products.

Stopping transmission

But the NICE guidance will only look at the risk of transmission fromtissues that potentially carry CJD and the tools used to operate onthese tissues.

CJD is a progressive, fatal neurological disease.

The most high-profile form of the disease, vCJD, is a human form ofbovine spongiform encephalopathy (BSE), also known as 'mad-cow disease'.

Tissues that are classed as having a high or medium risk for CJD andvCJD include brain and spinal cord, the front and back of the eye andthe inside of the nose.

Patients should be reassured that the risk of developing CJD as a resultof any operation is small.Professor Bruce Campbell, a surgeon and chairman of NICE's sub-committee

Surgery on lymph glands, such as tonsils, also carries the risk of vCJD.

NICE will advise surgeons on whether reusable instruments or disposableinstruments should be used in different procedures.

The only way that surgery can be made completely safe is to usedisposable instruments for all operations.

However, disposable versions of surgical instruments do not exist forall procedures.

Experts will have to balance the potential risks of transmitting CJD andvCJD via reusable instruments against the risks to patients of using"potentially technically substandard or unreliable disposableinstruments", said NICE.

It will also look at the way surgical instruments are sterilised andcleaned.

Professor Bruce Campbell, a surgeon and chairman of the sub-committeesaid: "Patients should be reassured that the risk of developing CJD as aresult of any operation is small.

"Our aim will be to make recommendations on clinical practice which willkeep the risk as close to zero as possible."

At present, it is not possible to know what the risk of transmission is.

About one in a million people have CJD and 142 people are known to havedied of vCJD since 1996.